Roller vane pump with integrated motor

ABSTRACT

A pump includes a housing with an inlet and an outlet, and a stator that generates a rotating magnetic field. A pressure boundary assembly defines a pumping chamber. A rotor mounted for axial rotation within the pumping chamber has salient poles to interact with the field. The rotor mounts eccentrically such that a gap between the rotor body and stator varies circumferentially. The rotor defines hollows intermediate the salient poles with cylindrical rollers for free radial movement therein. Fluid-filled volumes are formed between the housing, the rotor and the rollers. On each side of a plane passing through the rotor axis and the housing axis, the pumping chamber is in fluid communication with the inlet or outlet, respectively. As the rotor spins, expanding volume draws fluid from the inlet and contracting volume expels fluid from the outlet.

STATEMENT OF GOVERNMENT INTEREST

This invention was made with Government support under government contract NNC06CA34C awarded by the National Aeronautics and Space Administration to Protonex Corporation. The Government may have certain rights in the invention.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The subject invention is directed to a roller vane pump driven by an electric motor, wherein the rotor assembly of the electric motor also serves to pressurize the working fluid.

2. Description of Related Art

Pumps are well known in the art, and have been employed in a wide variety of application for many years. Most pumps utilize a motor to drive a drive shaft with a rotary impeller mounted thereon. Typically, large housings are required to contain the separate components. Pumps for the aerospace industry, fuel cell applications and the like must be designed with cost, size, weight, complexity, performance and durability requirements in mind.

In an effort to simplify pump design, U.S. Pat. No. 6,109,887, the disclosure of which is herein incorporated by reference in its entirety, has added a blade to a rotor to push the working fluid. The overall pump in U.S. Pat. No. 6,109,887 is still relatively large as a blade was simply added onto a traditional rotor. In view of the above, there is a need for an improved pump that has parts which serve multiple functions to simplify design and decrease the overall profile.

SUMMARY OF THE INVENTION

Pumps in accordance with the subject disclosure have numerous applications such as fuel cells or as a cooling pump for a spacecraft, avionics equipment or for computers and high-power electronics. Such pumps are miniature and can pump fluids in pumped two-phase electronics cooling loops and be used for any applications requiring a small pump.

The subject disclosure is also directed to a vane pump assembly including a cylindrical pumping wall having an inner circumferential surface defining a pumping chamber. A rotor assembly is eccentrically mounted with respect to the cylindrical pumping wall for axial rotation, the rotor assembly having a rotor body defining a plurality of circumferentially spaced apart radially extending vane pockets intermediate projections, each projection being magnetic. A cylindrical roller is supported in each radially extending vane pocket and a stator assembly surrounds the cylindrical pumping wall. The stator assembly has windings for generating a magnetic field to act upon the projections. A housing surrounds the stator assembly and defines inlet and outlet ports for ingress and egress of fluid.

Preferably, the rotor body has six projections and six vane pockets and the stator assembly has nine windings. The cylindrical pumping wall may include a closed end and an open end, which has been sealed to the housing to form a pressure boundary about the rotor assembly and within the stator assembly, wherein the open end of the cylindrical pumping chamber has a flange that is hermetically sealed to an annular groove formed in an inner face of the housing.

It should be appreciated that the present invention can be implemented in numerous ways, including as a process, an apparatus, a system, a device, and a method for applications now known and later developed. These and other features of the system disclosed herein will become more readily apparent from the following description and the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

So that those skilled in the art to which the subject invention appertains will readily understand how to make and use a vane pump of the subject disclosure without undue experimentation, preferred embodiments thereof will be described in detail below with reference to the following figures:

FIG. 1 is an exploded perspective view of a pump assembly of the subject disclosure.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

The advantages, and other features of the technology disclosed herein, will become more readily apparent to those having ordinary skill in the art from the following detailed description of certain preferred embodiments taken in conjunction with the drawings which set forth some representative embodiments of the present invention. All relative descriptions herein such as front, rear, side, left, right, up, and down are with reference to the Figures, and not meant in a limiting sense.

Referring now to FIG. 1, an exploded perspective view of a pump assembly 100 is shown. As will be appreciated by those of ordinary skill in the pertinent art, the pump assembly 100 utilizes similar principles to the pump assembly described in U.S. patent application Ser. No. 12/194,658 filed on Aug. 20, 2008, which is incorporated herein by reference in its entirety.

A feature of the pump assembly 100 is that the rotor assembly 140 is enclosed in a pressure boundary. By enclosing the rotor assembly 140, the number of sealed surfaces that can leak is reduced. Also, the working fluid is separated from the stator assembly 130 and electrical connections through the pressure boundary to the stator assembly 130 are not needed.

The pump assembly 100 is a roller vane pump with an electric drive motor contained within a housing (not shown). A stator assembly 130 and a rotor assembly 140 combine to form a permanent-magnet, brushless DC motor. The rotor assembly 140 serves combined duty as a rotor of the electric motor and as the fluid working element of the roller vane pump.

The rotor assembly 140 is mounted eccentrically with respect to the stator assembly 130. The rotor assembly 140 has a generally cylindrical rotor body 144 that includes a plurality of projections 141 extending radially therefrom, each projection 141 being a salient pole of the electrical drive motor. The rotor body 144 also defines elongated semi-oblong hollows 147 intermediate adjacent projections 141. The number of stator windings 131 and rotor projections 141 as well as the respective shapes, sizes, materials and strengths can be selected in accordance with known principles of electric motor design to obtain the desired torque and speed of the pump assembly 100.

The stator assembly 130 defines an inner bore 135 in which a pumping chamber sleeve 160 is located around the rotor assembly 140. The pumping chamber sleeve 160 has a closed end 162 and an open end 164. A flange 166 surrounds the open end 164. The inlet 126 a and outlet 126 b have pipes 151 a,b respectively coupled thereto. The rotor assembly 140 rotatably mounts on the bearing 146, which is held between mounts 133 on the end caps 122 a (only one shown).

The rotor assembly 140 is placed within the pumping chamber sleeve 160 and the flange 166 is hermetically sealed to an annular groove 128 formed in the inner face 129 of the front end cap 122 a. The front end cap 122 a may form inlet and outlet ports 126 a, 126 b within the annular groove 128 so that the working fluid may enter and exit the pumping chamber 170 formed with the pumping chamber sleeve 160. The stator assembly 140 fits over the pumping chamber sleeve 160 to generate a rotating electric field strong enough to penetrate the pumping chamber sleeve 160 and interact with the rotor assembly 140. As a result, the rotor assembly 140 is housed within a pressure boundary with the stator assembly 130 outside thereof.

A cylindrical roller 150 is disposed in each hollow 147 intermediate the salient poles or projections 141 of the rotor body 144. The rollers 150 are free to move within the hollows 47 but radially retained therein by the pumping chamber sleeve 160.

As a result of the eccentricity between the rotor assembly 140 and the pumping chamber sleeve 160, a space between the pumping chamber sleeve 160 and the projections 141 of the rotor body 144 varies. The position of the rollers 150 in the respective hollow 147 also varies depending upon the rotational position of the rotor body 144. Consequently, the volume between the rotor body 144, the pumping chamber sleeve 160 and adjacent rollers 150 varies depending upon the rotational position of the rotor body 44.

In operation, the windings 131 of the stator assembly 130 are energized in sequence to provide a rotating magnetic field. The magnetic field interacts with the salient poles or projections 141 to rotate the rotor assembly 140. On each side of a plane passing through the rotor axis and the pumping chamber sleeve axis, the pumping chamber is in fluid communication with the inlet 126 a or outlet 126 b, respectively. As the rotor body 144 spins due to the rotating magnetic field, the fluid-filled volumes expand on one side of the plane and contract on the other side of the plane. The expanding volumes draw fluid from the inlet 126 a and the contracting volumes expel fluid from the outlet 126 b.

It is to be appreciated that the subject disclosure includes many different advantageous feature, each of which may be interchanged in any combination on like pump assemblies. While pump assemblies of the subject invention have been shown and described with reference to preferred embodiments, those skilled in the art will readily appreciate that various changes and/or modifications may be made thereto without departing from the spirit and scope of the subject invention as defined by the appended claims. 

1. A vane pump assembly comprising: a) a pressure boundary assembly defining an enclosed interior with inlet and outlet ports for ingress and egress of fluid and having a cylindrical pumping wall defining a pumping chamber; b) a rotor assembly eccentrically mounted within the pumping chamber for axial rotation, the rotor assembly having a rotor body defining a plurality of circumferentially spaced apart radially extending vane pockets intermediate projections, each projection being magnetic; c) a cylindrical roller supported in each radially extending vane pocket; d) a stator assembly surrounding the pressure boundary assembly and having windings for generating a magnetic field to act upon the projections; and e) a housing surrounding the stator assembly.
 2. A vane pump assembly as recited in claim 1, wherein the pressure boundary assembly includes a pumping chamber sleeve with a closed end and an open end enclosed by an end cap.
 3. A vane pump assembly as recited in claim 2, wherein the stator assembly fits over the pumping chamber sleeve to generate a rotating electric field strong enough to penetrate the pumping chamber sleeve and interact with the rotor assembly.
 4. A vane pump assembly as recited in claim 1, further comprising a flange surrounding the open end for sealing to the end cap.
 5. A roller vane pump assembly comprising: a) a housing defining an interior, at least one inlet for admitting fluid in and at least one outlet for allowing fluid out of the interior; b) a stator assembly within the interior having a stator and windings for generating a rotating magnetic field; c) a pressure boundary assembly defining an enclosed pumping chamber about a first axis within the interior; c) a rotor assembly mounted for rotation about a second axis within the pumping chamber, the rotor assembly including a body having projections that act as salient poles to interact with the rotating magnetic field, the body also defining a plurality of hollows intermediate the projections, wherein the rotor assembly is mounted eccentrically with respect to the pumping chamber such that a plane substantially passing through the first and second axis defines first and second sides of the body; and d) a cylindrical roller is disposed in each hollow for free radial movement within the hollow, wherein as the body spins due to the rotating magnetic field, volumes between adjacent rollers, the rotor assembly and the pumping chamber expand on the first side of the rotor drawing fluid from the at least one inlet and contract on the second side expelling the fluid from the at least one outlet.
 6. A vane pump assembly as recited in claim 5, wherein the stator assembly further comprises a filler material that defines the pumping chamber and secures the stator assembly in place.
 7. A vane pump assembly as recited in claim 5, further comprising a permanent magnet coupled to each projection.
 8. A vane pump assembly comprising: a) a pressure boundary assembly including a cylindrical pumping wall having an inner circumferential surface defining a pumping chamber; b) a rotor assembly eccentrically mounted for axial rotation and sealed within the cylindrical pumping wall, the rotor assembly having a rotor body defining a plurality of circumferentially spaced apart radially extending vane pockets intermediate projections, each projection being magnetic; c) a cylindrical roller supported in each radially extending vane pocket; d) a stator assembly surrounding the pressure boundary assembly and having windings for generating a magnetic field to act upon the projections; and e) a housing surrounding the stator assembly and defining inlet and outlet ports for ingress and egress of fluid. 